Photochemistry of 3,7-Bis(arylmethylene)bicyclo[3.3.1]nonane Derivatives

UV irradiation of trans-trans-3,7-bis(arylmethylene)bicyclo3.3.1]nonane-2,6-diones leads to their complete or partial transformation into the corresponding cis-cis isomers. Irradiation of trans-trans-3,7-bis(arylmethylene)bicyclo3.3.1]nonane-2,6-diol in ether in the presence of CuCl results in intramolecular cyclization involving the exocyclic double bonds and one benzene ring to give exo-7endo-10-dihydroxy-2-phenyl-3,4-benzotetracyclo4.3.3.18,11.01,6]tridecane.